mm, memcg: add rss_huge stat to memory.stat

This exports the amount of anonymous transparent hugepages for each
memcg via the new "rss_huge" stat in memory.stat.  The units are in
bytes.

This is helpful to determine the hugepage utilization for individual
jobs on the system in comparison to rss and opportunities where
MADV_HUGEPAGE may be helpful.

The amount of anonymous transparent hugepages is also included in "rss"
for backwards compatibility.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 09027a9fece5..ddf4f93967a9 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -480,7 +480,9 @@ memory.stat file includes following statistics
 
 # per-memory cgroup local status
 cache           - # of bytes of page cache memory.
-rss             - # of bytes of anonymous and swap cache memory.
+rss             - # of bytes of anonymous and swap cache memory (includes
+                transparent hugepages).
+rss_huge        - # of bytes of anonymous transparent hugepages.
 mapped_file     - # of bytes of mapped file (includes tmpfs/shmem)
 pgpgin          - # of charging events to the memory cgroup. The charging
                 event happens each time a page is accounted as either mapped